TM4C1292NCZAD Datasheet, PDF (1485/1844 Pages) Texas Instruments – Tiva Microcontroller

Tiva^™ TM4C1292NCZAD Microcontroller
Bit/Field
17
16
15:0
Name
VTIM
ETV
VL
Type
RW
Reset
0
Description
VLAN Tag Inverse Match Enable
Value Description
0 VLAN perfect matching is enabled. The frames with matched
VLAN tag are marked as matched.
1 VLAN tag inverse matching is enabled. The frames that do not
have matching VLAN tag are marked as matched.
RW
0
Enable 12-Bit VLAN Tag Comparison
Value Description
0 All 16 bits of the 15th and 16th bytes of the received VLAN frame
are used for comparison and VLAN hash filtering.
1 A 12-bit VLAN identifier is used for comparing and filtering
instead of the complete 16-bit VLAN tag.
Bits [11:0] of VLAN tag are compared with the corresponding
field in the received VLAN-tagged frame. Similarly, when
enabled, only 12 bits of the VLAN tag in the received frame are
used for hash-based VLAN filtering.
RW
0x0000 VLAN Tag Identifier for Receive Frames
This field contains the 802.1Q VLAN tag to identify the VLAN frames
and is compared to the 15th and 16th bytes of the frames being received
for VLAN frames. The following list describes the bits of this field:
■ Bits [15:13]: User Priority
■ Bit 12: Canonical Format Indicator (CFI) or Drop Eligible Indicator
(DEI)
■ Bits[11:0]: VLAN tag's VLAN Identifier (VID) field
When the ETV bit is set, only the VID field (Bits[11:0]) is used for
comparison. If VL[11:0] is all zeros when the ETV is set, the MAC does
not check the fifteenth and 16th bytes for VLAN tag comparison, and
declares all frames with a Type field value of 0x8100 or 0x88A8 as VLAN
frames.
June 18, 2014
Texas Instruments-Production Data
1485